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Comprehensive analysis of CNC machine tools

Posted by: Chris Na 2021-05-26 Comments Off on Comprehensive analysis of CNC machine tools

Due to the characteristics of high processing accuracy and high productivity of cnc machine tools, the proportion of applications in the manufacturing industry is increasing, which effectively guarantees product quality and output. Purchasing new CNC machine tools is a way to improve the efficiency of CNC machine tools, and the CNC transformation of old machine tools is also an important way to improve the efficiency of machine tools. The CNC transformation of machine tools can reduce the cost of purchasing CNC machine tools and save money for enterprises. In recent years, with the expansion of domestic demand for the transformation of various types of machine tools, machine tool transformation has gradually formed an industry, most of which are the numerical control transformation of old CNC machine tools, and some are the numerical control transformation of ordinary machine tools. Our company now introduces the problems that should be paid attention to in the process of CNC transformation of machine tools as follows for your reference.

1. Cost-effective analysis of CNC transformation and update of machine tools
Before the CNC transformation of the old machine tools, the price of CNC machine tools with the same performance on the market should be investigated. When comparing the prices of the two, the delivery time should also be considered. For low-priced small CNC lathes and milling machines, it is recommended to update and purchase new machine tools instead of rebuilding old ones. Because the cost of the two is similar, the savings are less, and the machine tool transformation time is about 2 months. For small CNC lathes and milling machines, machine tool manufacturers generally have stocks. It is a better choice to carry out numerical control transformation for large-scale and higher-priced machine tools, which can not only save more money, but also shorten the purchase time. For example, a horizontal machining center with a table size of 2000×1800mm, three-axis linkage, and 60 tools is as follows.
2. Investigate the status quo of machine tools that need to be modified
Not all old machine tools are suitable for numerical control transformation, and a comprehensive understanding of the machine tools that need to be transformed should be carried out.
The mechanical system of the machine tool must be surveyed and mapped correctly. Good mechanical performance is the basic condition for the successful CNC transformation of the machine tool. Otherwise, no matter how good the CNC system is, it will not be able to exert its due performance. Therefore, the mechanical accuracy of the machine tool should be tested before the CNC transformation of the machine tool, and the problems found can be repaired during the implementation of the machine tool transformation. If there are many problems in the mechanical system of the machine tool, such as defects in the mechanical structure design and manufacturing of the old machine tool, the CNC transformation of the machine tool will not be of much significance.
The electrical system of the old machine tool continues to fail due to the aging of the components, which is the focus of the machine tool transformation. To understand the old machine tool numerical control system manufacturer model, the number of control axes, the spindle and feed axis drive configuration, the power of the spindle motor, the torque of the feed axis motor, etc.
Check whether the random technical information is complete and complete. Complete technical information can shorten the technical preparation time for machine tool transformation. Among them, electrical schematic diagrams, PLC programs, machine tool maintenance manuals, hydraulic, pneumatic, lubrication schematic diagrams, mechanical assembly diagrams, etc., must be carefully studied. Special attention should be paid to the fact that the content provided in the technical data may be wrong and inconsistent with the actual machine tool. This is because some machine tool manufacturers provide general drawings of series models, and the electrical hardware changes of individual machine tools are not marked in the electrical data. This requires us to compare the actual machine tool and carefully check to avoid mistakes.
Third, the determination of the CNC transformation plan of the machine tool
On the basis of machine tool surveying and mapping, the overall machine tool transformation plan is determined according to the user’s requirements.
1. The transformation plan of the numerical control system
The transformation of the machine tool is first of all the transformation of the numerical control system. According to the existing control level of the machine tool, the processing requirements of the workpiece, and the capital status of the enterprise, the corresponding low, medium and high-end numerical control systems are selected. When choosing a numerical control system, you need to consider the products of mainstream manufacturers. For example, foreign numerical control systems can choose FANUC, Siemens systems, etc., and domestic numerical control systems can choose Huazhong and Kanedi systems. It should also be as consistent as possible with the CNC system selection of other CNC machine tools for machine tool users. The advantage of this is that it is convenient for maintenance personnel to maintain the machine tool; the more centralized CNC system also facilitates the reduction of the types of spare parts. The selection of the CNC system is based on the principle of practicality, and there is no need to waste money in pursuit of a higher level.
2. The transformation plan of the spindle servo system
The spindle control of old CNC machine tools generally uses DC servo or AC analog servo drive system (usually +/-10V analog signal). According to the needs of use, the original drive device and spindle motor can be used instead of the AC digital servo drive system or inverter control. The original drive system can also be retained, such as a good AC analog servo drive system; the DC servo drive system can retain a good DC motor and use a new DC servo control device to replace the old drive device.
3. The reform plan of the feed servo system
Similar to the reconstruction plan of the spindle servo system, according to the use needs, the original drive device and motor can be replaced by an AC digital servo drive system; the original drive system, such as a good AC analog servo drive system, can also be retained.
4. Modification plan of closed-loop control detection device

For the induction synchronizer/ruler of the old machine tool, it can be replaced by circular grating and grating ruler. When selecting the model, pay attention to the consistency of the interface signal between the detection element and the system, square wave signal or voltage signal. If you retain the old current signal grating ruler, you need to install a current signal to voltage signal conversion device to match the new system, because most of the new systems do not support current signals.